Impact Assesment of Salt Gradient Solar Pond Against Global Energy Crises

Volume-4, Issue-2, April-2014, ISSN No.: 2250-0758 International Journal of Engineering and Management Research Available at: www.ijemr.net Page Number: 88-91

Impact Assesment of Salt Gradient Solar Pond against Global Energy Crises

Sunil Kumar¹, S. K. Singh2 1Assistant Professor, Mechanical Engineering Department, B.I.T Sindri, Dhanbad, Jharkhand, INDIA 2Director, Mechanical Engineering Department, B.I.T Sindri, Dhanbad, Jharkhand, INDIA

ABSTRACT in the worlds energy consumption can flatten out and the The purpose of this paper is to present a concise climatic threat can be handled with the help of among overview of the progress of technology, economic condition other things increasing the share of renewable energy and market in relation to renewable energy. The use of Fossil sources. fuels in the transport sectors and the energy provision should Despite of having certain shortcomings which can not continue like today’s energy demand for day to day life. be also avoided solar energy plays great importance in The increase in GREENHOUSE GAS emissions recommends the countries to change the energy consumption and to base power substitution. This energy can be captured, their welfare on a sustainable development. In 21st century converted, and distributed in ACTIVE and PASSIVE not only with rapid growth of technological advancement but ways. Active solar energy techniques uses photovoltaic also due to richness of their technological option, application, panels and solar thermal collectors to harness the energy widespread availability and from environmental perspective where as Passive solar techniques includes orienting a we are thinking of renewable energy that comes from buildings to the sun, a selecting materials with favorable continually replenished resources like solar energy, wind thermal mass or light dispersing properties and designing energy Tidal energy, Geo-thermal energy etc.Though fossil spaces that naturally circulates air. By producing solar fuels have limited supply, 90% of worlds energy is derived electricity which is convenient for both remote areas and from it. But the rate at which we are consuming that cannot be created and they are not environment friendly. From cities will be helpful to meet our energy need in large, if analysis it has been predicted that oil and gas are to be the government continues to invest in alternative energy so exhausted by 2045 and 2055 and after that coal. Hence we are that we will be aware and work more on this energy to expected to face global challenge regarding power supply in avoid the forthcoming power crises. coming near future as the global requirements for energy has Among all renewable energy sources solar energy been continuously increasing for more than a century is considered as the best one because influenced by population growth and industrial development. (i) It is free source of energy. (ii) It is clean and environmentally friendly source of energy. Keywords: Solar Pond, Photovoltaic green house, Energy, (iii) It cuts down electricity bill. Heat Engine. (iv) This industry is the fastest growing industry to create new job. I. INTRODUCTION (v) Solar energy can be trapped using solar panel having lifespan of around 20+ years and requires less With the exception of geo-thermal energy, tidal maintenance. energy, solar energy is the driving force behind all other 1.2 CHALLENGES TO USE SOLAR ENERGY renewable energy sources. The average daily solar energy The most important disadvantages about solar incident in India is 5kwh/m2.It is located between 20.30- energy is that it can be assessed on a short term basis. The 26.38 north Latitude and 88.04-92.44 degree east total incoming radiation normally doesn’t vary much from Lattitude.It is an ideal location for solar energy utilization. year to year (typically+5%) but it is not easy to predict on 1.1 CHALLENGES FOR FUTURE EXPANSION OF a day today basis. If one has to trust solar energy as the RENEWABLE ENERGY only energy source either one has to adjust to the variation The International energy agency (IEA) doesn’t only point given by nature, store the energy or invest in an alternative to renewable energy sources as climatic, environmental system to cover the energy demand when the sun doesn’t friendly which measures in future society. They pointed shine. out that the highly consumption of fossil fuels will increase 88

Outside the Earths atmosphere the solar radiation convenient and effective means which collects solar intensity is relatively constant at 1367w/m2 + 3%.The radiations and stores its thermal energy for a relatively variation is due to the distance between the earth and the longer period of time. Research effort and publication on sun changing throughout the year. The suns radiation solar pond started in 1960 in Israel. After the energy crises changes because of fluctuations in the inner physical in 1970 it speeded throughout the world it is now very process. On average approximately 30% of the suns common in ISRAEL, USA, INDIA, AUSTRALIA.CHINA radiations is reflected before it reaches to the ground. has done remarkable progress in study and application of These incoming radiations which is at disposal for solar pond technology to various applications. energetic exploitation depends on A Solar pond is a shallow body of water which acts as a (i) One,/s location on the planet, because closer to the poles solar collector with integral heat storage for supplying the sun is lower in the sky then at the equator thermal energy. Solar ponds are mainly two types- (ii) Time of the year, because the sun is having higher intensity in the sky during summer then during winter except from the tropics. (iii) Local circumstances such as local cloud formation and shadows from surroundings nature and buildings. Solar energy that reaches the earths surfaces consists of two components (a) Direct incoming radiation

(b) Diffuse incoming radiation As salt gradient solar pond is a pool of water about 1—5 m Sun emits enormous amounts of energy, its fraction of deep which contain dissolved salts to establish a stable solar radiation which reaches the earths surface is more density gradient. Commonly three layers in SGSP are than 10,000 times the world’s energy consumption. (i) Upper convective zone (UCZ) 1.3 BARRIERS OF THE APPLICATION FOR SOLAR (ii) Lower convective zone (LCZ) ENERGY (iii) Salinity gradient or Non convective zone (NCZ) (I) Lack of information of available technologies and their optimal design and integration in heating system. (II) Lack of local skills for production and installation. III. SALT GRADIENT SOLAR POND (III) Lack of assessment of solar energy for active solar heating. It is almost always possible to find a place for the solar The SGSP is the most eco friendly and environmental collection with enough sunshine. For Passive solar energy friendly among all the solar energy system for electricity where the solar energy is typically coming through normal generation, desalination, hot water application in windows, neighbouring buildings or long trees can give a agriculture, greenhouse heating, domestic hot water severe reduction of the solar energy gradient. application, space heating and cooling of buildings .A SGSP is more cost effective since its collection cost per square meter is only 1/5thof that of a liquid flat plate II. SOLAR POND collector and cost1 kwh of electricity production by SGSP is only 1/5thof that produced by photovoltaic cells. While developing a thermal storage system it is useful to link at the storage capacity of the proposed material which is referred to volumetric heat capacity or most commonly the specific heat and rate at which material can take up and store heat.

3.1 WORKING PRINCIPLE OF SOLAR POND When solar radiations fall on the surface of the SGSP Previous studies and research have given idea for most of the radiations penetrates and absorbed at the low cost collection and storage system of solar energy in bottom of the pond. The temperature of the dense salt layer various countries. Simultaneous collection and storage of increases. If there is no salt at the bottom layer it would solar energy is feasible in a purposely built open water become less dense then the top layer and the buoyancy reservoir commonly called SOLAR POND. It is a effect would cause this water rise up and thus the layer 89

would mix getting heat from the top of the surface of the The thermal efficiency of salt gradient solar pond is higher pond and then rapidly dissipated to the surrounding. But than that of a flat plate collector when the operating the denser salt layer at the bottom of the SGSP prevents temperatures are higher and is in the range of 20-30 % the heat to be transferred to the top layer of fresh water by when the temperature difference is around 40 to 600c. The natural convection. Due to this temperature of the bottom thermal efficiency is strongly dependent upon the layer may rise up to 95oc making the SGSP a unique transparency of the pond which is influenced by the energy trap with added advantage of constructing in long presence of algae and dust. Even if the solar pond is free of term heat storage capacity. dust and algae, the absorption properties of pure water 3.2 THERMAL PERFORMANCE OF SALT influence the transmission of solar radiation in the pond. GRADIENT SOLAR POND The transmissivity of solar radiation in pure distilled water The Thermal efficiency is strongly depended observe that about half the solar radiation is absorbed in upon the transparency of the pond which is influenced by the first 40 centimeter of water. This is on account of the presence of algae and dust. Even if the solar pond is strong infrared absorption bands in water. At a depth of 2 free of dust and algae the absorption properties of pure meter the transmission is about 40%.The thickness of water influence the transmission of solar radiation in the gradient zone must be chosen depending on the pond .The thermal efficiency of solar pond is higher than temperature at which thermal energy is required. If the that of flat collector. When the operating temperature are thickness of gradient zone is too high the transmission of higher and it is in the range of 20-30% and the temperature solar radiation is reduced while if it is too low it causes difference around 60° C. The transmissivity of solar high heat losses from the bottom to the top of the pond. radiation in pure distil water observed that half the solar The optimum value of the thickness depends on the radiation is absorbed in the 1st 50 cm of water .This is an temperature of storage zone of the pond since temperature account of strong infrared absorption bands in water. At is proportional to solar intensity .It was observed that the depth of 2 meter the transmission is about 40%. The temperature profile was established in the pond only after thickness of the gradient zone must be chooses depending five days of heating. on the temperature at which thermal energy is needed. If the thickness of the gradient zone is too high the transmission of the solar radiation is reduced while if it is too small its causes high heat losses from the bottom to top of the pond. The optimum value of thickness depends on the temperature of storage zone of the pond since temperature is directly proportional to solar intensity.

5. A great factor in the future of solar pond operation is the implementation of an acceptable means of salt recycling. It is major point when a solar pond is to be used on a farm or private land. 6. Solar pond is high promising for the tropics and the lower latitude for the electric power generation.

V. REFERENCES

[1] Hottel H.C. and Wortz B C : Performance of Solar plate Collector ASME 64,91 (1942) [2] Seigel L G : The effect of turbulence promoters on heat transfer coefficient for water flowing in horizontal The thermal performance of the prototype salt tubes ASME (1946). gradient solar pond constructed at B.I.T.Sindri Dhanbad [3] Patel S.M. Gupta CL (1981) –Experimental solar pond near Heat Engine Laboratory in the Mechanical in an hot humid climate sun world 5(115-118). Engineering Department having dimension of 6ftx4ftx2ft [4] Hull JR (1990). Maintenance of brine transparency in and thickness of the surface , gradient and storage zone are salinity gradient solar pond J..Solar Energy 112.65-69. 0.5m,1.0m, 1.0m in different conditions are as follows [5] Kooi.CF(1979) .The steady state salt gradient solar (a) Solar pond without water pond technology 33 (37-45). (b) Solar pond filled with water are 7.99 [6] C. F. Kooi- Salt gradient solar pond with effective (c) Solar pond filled with brine water are 9.62 bottom. Solar Energy 26,113 (1981). (d) Solar pond with brine water and covered with [7] M. N. A. Hawaldar and B.J. Brinkworth- An analysis transparent plastic sheet are 10.6 of the non convective solar pond. Solar Energy (e) Solar pond with brine water covered with transparent 33(391)1984. plastic sheet and booster mirrors are11.55 [8] A. Guha – Analysis of heat transfer in solar pond M. E. Project Mechanical Engineering Department. Indian Institute of Science ( India). [9] Kanayama K Inaba H., Baboh & Fukuda T.(1991) Experimental Analysis of Particle scale Solar pond staglzed with salt gradient solar pond 46.6,353-359. [10] Karaklick M (1998) Determination of the performance of an insulated pro type salt gradient solar pond. [11] Kameruip K and Oda.T (1991) Thermal performance of shallow solar pond water heater with semi transportation multilayer surface insulation Solar energy 16.10(1239-1245).

IV. CONCLUSION

1. Solar pond is an efficient source of renewal heat energy. 2. Solar pond is environmentally sustainable. 3. The great advantage of solar pond is it posses to built in long term thermal energy storage which no other solar connection devices match. 4. It can be economically constructed if there is plenty of in expensive salt, flat land and easy asses to water.